In the fig.1, above the top of the arc is developed. Counter balance and tipping onto the new edges is accomplished. The inside leg is beginning to flex and tip.
Notice how the inside foot is held back from pushing forward?
To keep the inside foot pulled back at this speed and angle, requires strong movement focus. This doesn't come naturally, it needs work.
The inside arm and shoulder although they look to be in the same relationship through the whole arc are actually moving forward to keep this relationship. If this is not done energetically enough, rotation of the upper body relative to the skis results.